Control devices



July 2, 1968 J. c. DAWSON I CONTROL DEVICES Filed Nov. 18, 1965 t I 7 MM INVENTOR- ATTORNEY United States Patent 3,390,696 CONTROL DEVICESJoseph Carl Dawson, 93 Ford Lane, Hazelwood', Mo. 63042Continuation-impart of application Ser. No. 358,355, Apr. 8, 1964. Thisapplication Nov. 18, 1965, Ser. No. 508,533

4 Claims. (Cl. 137-496) This invention relates to valves, and moreparticularly to check valves adapted to permit the flow of fluid in onedirection, but prevent flow in an opposite direction.

This application is a continuation-in-part of my copending applicationSer. No. 358,355, filed Apr. 8, 1964, now abandoned.

Briefly, this invention comprises a body having an inlet and an outletleading to a cavity in the body, a diaphragm extending across the cavitythereby dividing it into two chambers, the diaphragm being adapted toopen and close a port leading to the outlet in response to variouspressure conditions on the inlet and outlet sides of the body.

Among the several objects of the invention may be noted the provision ofa check valve which is thoroughly dependable under very lowback-pressure conditions; the provision of a check valve which ejects asmall quantity of fluid out through the inlet thereof when subjected toa back pressure, which small quantity of fluid can be used toperformuseful work; the provision of a valve of the class described which ishighly responsive and effectively prevents back flow when the pressureat its outlet exceeds the pressure at its inlet; and the provision ofsuch a check valve which is simple and economical in construction. Otherobjects and features will be in part apparent and in part pointed outhereinafter.

The invention accordingly comprises the constructions hereinafterdescribed, the scope of the invention being indicated in the followingclaims.

In the accompanying drawings, in which several of various possibleembodiments of the invention are illustrated,

FIG. 1 is a plan view of a check valve constructed in accordance withand embodying the present invention;

FIG. 2 is a section taken along line 22 of FIG. 1;

FIG. 3 is a section similar to FIG. 2 showing a second embodiment ofthis invention;

FIG. 4 is a section similar to FIG. 2 showing a third embodiment of thisinvention;

FIG. 5 is a plan view of a modified diaphragm which may be used when thechamber in the valve is rectangular in shape rather than circular inshape.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawmgs.

There are many types of check valves adapted to permit the flow of fluidin one direction but prevent flow in an opposite direction. One' of themost common types of check valves is the ball type which includes asphere biased, by gravity or a spring, for example, toward a seat.Fluid, when forced through the valve in one direc tion, pushes thesphere off the seat, but when the force driving the fluid is stopped orwhen back pressure develops, the sphere is forced back on the seat toinhibit back flow. While the known types of check valves performadequately in many situations, such valves are not entirely satisfactoryunder very low back-pressure conditions. Often such valves permit aslight amount of fluid to bleed back past the valve under lowback-pressure conditions.

Moreover, in the chemical industry, in particular, it is often desirableto mix two or more liquids together, generally in a mixing chamber,which react somewhat ice violently in certain cases to form a desiredend product. If for some reason one of the chemical feeder lines wassubjected to a back pressure and chemicals from the other lines therebyforced into it, the reaction would occur in the particular feeder linesubjected to the back pressure which would be undesirable. For thisreason, check valves are often installed in such chemical feeder lines.Many check valves of current manufacture, however, are not responsive tolow back pressures of a magnitude of three to four inches of water, and,therefore, cannot be utilized in conjunction with certain chemicalmixing processes. An example of such a mixing process is disclosed in mycopending application Ser. No. 361,201, filed Apr. 20, 1964, now U.S.Patent 3,245,585.

According to the present invention, a check valve is provided which ishighly responsive and thoroughly dependable under very low back-pressureconditions. Moreover, the valve, in addition to being thoroughlydependable under low back-pressure conditions, is dependable under highpressure conditions, and thus may be utilized in both high and lowback-pressure condition situations.

Referring now to the drawings, a valve of this invention is generallyindicated in FIG. 1 at 1. Valve 1 includes a body 3 having two circularmembers or parts 5 and 7 secured together in face-to-face relation byfasteners 9, such as bolts, for example.

The inside faces of parts 5 and 7 are provided with aligned matchingcylindrical recesses 11 and 13, respectively, which together form acavity 15. The parts 5 and 7 may be made of various materials, such asplastic or metal, for example. A diaphragm 17, which may be of anyconventional impermeable diaphragm material, such as rubber or syntheticplastic, for example, extends across the cavity 15 and is clampedbetween parts 5 and 7. The diaphragm thus makes separate compartments orchambers of recesses 11 and 13. A ring-shaped ridge 19 on part 7 mateswith a groove 21 in part 5 to clamp the diaphragm 17 securely inposition.

An inlet port 23 is provided in part 5. A passage 25 leads from inletport 23 to the recessed portion 11 of cavity 15. A cylindrical boss 27located approximately in the center of recess 11 extends towarddiaphragm 17. Boss 27 has a substantially flat seat on its outer end,and has a passage 29 therein extending to an outlet port 31. A passage33 extends from outlet 31 to the inside face of part 5, where it isaligned and in registration with a passage 35 in parts 7 extending tothe recessed portion 13 of cavity 15. Thus the recessed portion 13 is inconstant communication with outlet port 31 through the passages 33 and35.

When a negative pressure differential is created across the valve, thatis to say when the pressure at the inlet port 23 exceeds the pressure atthe outlet port 31, the valve allows fluid to pass therethrough andoperates as follows:

The pressurized fluid enters valve 1 through inlet port 23 and passesthrough passage 25 into recess 11 Where it bears against diaphragm 17causing the same to flex to the right, that is to say, into the chamberdefined by the recess 13 as indicated by the broken lines in FIG. 2.Communication is thereby established between passages 25 and 29 andfluid is allowed to flow through valve 1 from inlet port 23 to outletport 31. As long as the pressure at inlet port 23 remains greater thanthe pressure at outlet port 31, diaphragm 17 will be biased away fromthe end seat of cylindrical boss 27 and into the chamber defined byrecess 13, whereby fluid is allowed to pass through recess 11 and intopassage 29.

However, when valve 1 is subjected to a back pressure, that is to say,when the pressure at outlet port 31 exceeds the pressure at inlet port23, diaphragm 17 flexes in the opposite direction, that is to say movesto the left as seen in FIG. 2, and seals passageway 29. Moreparticularly, the pressure within recess 17 at all times equals thepressure at outlet port 31 inasmuch as the two are interconnected byrelatively short passages 33 and 35. When this pressure exceeds thepressure at inlet port 23 which is substantially equal to the pressurein recess 11, diaphragm 17 flexes into the chamber defined by recess 11as indicated by the broken lines appearing in FIG. 2, and intosealing-wise engagement with the flat end seat of cylindrical boss 27 soas to preclude reverse flow of fluid out of passage 29. Once diaphragm17 engages the flat seat of boss 27, the closure force presented ondiaphragm 17 is substantially increased for the area subjected to theback pressure, that is to say, the right hand side of the diaphragm asseen in FIG. 2, is substantially greater than the area presented towardthe low pressure in recess 11. Thus, a tight seal is obtained under backpressure conditions which completely blocks passage 29 and prevents anyreverse flow of fluid therethrough.

Moreover, the fiexure of diaphragm 17 into recess 11 under back-pressureconditions decreases the volume of the chamber formed by such recess 11and forces a small amount of liquid out through inlet port 23. Thissmall amount of liquid or so-called back flow can be used to performuseful work and has been found particularly useful in an apparatus foradding measured amounts of one or more fluids to other fluids, whichapparatus is described in detail in my copending application Ser. No.361,201 filed Apr. 20, 1964, now US. Patent 3,245,585. Generallyspeaking, that apparatus comprises a vertically presented cylindricalmeasuring chamber having an inlet at is lower end and an outlet at itsupper end. The outlet inwardly terminates at a circular seat and is eX-teriorly connected to the inlet port 23 of a chack valve 1 of thepresent invention. The cylindrical chamber internally retains ameasuring sphere which is carried upwardly by the momentum of the fluidpassing through the chamber, which momentum is, of course, generated bya pressure differential between the inlet and outlet of the entiredevice. When the sphere engages the circular valve seal within themeasuring cylinder, the fluid flow is immediately block. When a backpressure is presented at the outlet port 31 of the valve 1, a smallamount of fluids is ejected through the inlet port 23 thereof aspreviously described herein, which back flow is transferred through theoutlet of the measuring cylinder thereby unseating the sphere from thevalve seat so it can descend through the cylinder into position foranother measuring cycle. If this back fiow did not occur, the measuringsphere would remain firmly engaged with the valve seat at the upper endof the measuring cylinder and the entire device would not be capable ofcyclic operation.

While the valve of this invention as shown in FIG. 2 is effective in theprevention of back flow, additional force may 'be applied on theright-hand side of the diaphragm to cause the latter to close passage 29by placing a compression spring in recessed portion 13 so that it willreact against part 7 to force the diaphragm toward passage 29. Thespring would then supplement the pressure on the right-hand side of thediaphragm for forcing the latter to the left. However, if the valve 1 islocated in a system wherein fluids highly corrosive to metals areemployed, a metal spring might soon be rendered useless.

A second embodiment of this invention is shown in FIG. 3 It is generallysimilar to the embodiment shown in FIGS. 1 and 2 and includes parts 5aand 7a secured together with a diaphragm 17a therebetween. A passage 25aleads from an inlet port 23a to a recessed portion 11a of a cavity a. Apassage 29a extends through a cylindrical boss 27a and part 5a to theinterface of the part 5a. A plug 37 closes one of the bores of port 29a.A passage 35a in part 7a registers With the interface opening of passage29a and extends to a recessed portion 13a of cavity 15a. An outlet port31a is connected with recessed portion 13a by a passage 39. Theoperation of the valve 1 shown in FIG. 3 is generally the same as theoperation of the embodiment shown in FIGS. 1 and 2. When suction isapplied to outlet port 31a, diaphragm 17a is drawn away from the passage29a and fluid is drawn through the valve 1. When back pressure iscreated the diaphragm 17a is forced against boss 27a and closes passage29a. Fluid forced through the valve 1 by pressure on the inlet sideforces the diaphragm 17a to the right as viewed in FIG. 3 to openpassage 29a.

Another embodiment is shown in FIG. 4. It also is generally similar tothe embodiment shown in FIGS. 1 and 2, but the port 25b, which issimilar to port 25, extends through the cylindrical boss 27b, ratherthan opening into the chamber at one side of the boss. The operation ofthis embodiment is similar to the embodiment shown in FIGS. 1 and 2.

A rectangular diaphragm 41 is illustrated in FIG. 5. This diaphragm isadapted for use in valves of this invention having rectangular recessesin the parts thereof so as to form a rectangular chamber, rather thancircular recesses such as described above. If the recesses shown inFIGS. 2, 3 and 4 were rectangular rather than circular, diaphragm 41would be used in place of diaphragms 17 or 17a. Diaphragm 41 includes aflexible border portion 43 and a relatively stiff rectangular centerportion 45'. Holes 47 may be provided so that bolts may pass through thediaphragm. Since pressure, when applied to a rectangular diaphragm,causes a degree of deflection from the center of the diaphragm to thesides which is different from the degree of deflection from the centerto the ends, the stiffened center portion is provided so that it willseat upon the boss and close the port 29 or 29a. The flexible borderportion 43, upon the creation of back pres sure, will be forced towardthe recess in which the boss is located so that the stiffened portion 45is firmly held in its seated position.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

1. A check valve for blocking a fluid line when the fluid therein issubjected to back pressures of extremely small magnitude: said checkvalve comprising a body having an inlet port, an outlet port, and aninternal cavity; a flexible continuous unobstructed diaphragm extendingacross the cavity whereby the cavity is divided into first and secondchambers; and a boss secured to the body and projecting inwardly throughthe first chamber where it terminates in a substantially planar seatingface located parallel and in close proximity to the diaphragm; the bodybeing provided with a first passage interconnecting the inlet port andfirstchamber, a second passage which communicates with the outlet portat one end and at its other end terminates at the seating face of theboss in the formation of an orifice, and a third passage forestablishing communication between the outlet port and the secondchamber; the diaphragm being adapted to flex away from the seating faceso as to reduce the volume of the second chamber when the pressure atthe inlet port exceeds the pressure at the outlet port whereby toestablish communication between the inlet and outlet ports for thepassage of fluid through the check valve, the diaphragm being adapted toflex toward the boss and into sealingwise engagement with the seatingface when the pressure at the outlet port exceeds the pressure at theinlet port, whereby the orifice is blocked so as to precludecommunication between the outlet and inlet ports, the diaphragm beingfurther adapted to flex beyond the seating face when pressure at theoutlet port exceeds the pressure at the inlet port to reduce the volumeof the first chamber and to force a small quantity of fluid out of theinlet port to perform useful work.

2. A check valve according to claim 1 wherein the body comprises firstand second matching members secured together in face-to-face relation,the members being relieved in the provision of first and second opposedmatch ing recesses, the boss projecting into the first recess, and thediaphragm being interposed between the first and second members.

3. A check valve according to claim 1 in which the first passage extendsthrough the boss and terminates at the seating face.

4. A check valve according to claim 2 in which the first and secondrecesses and the 1308s are cylindrical.

6 References Cited UNITED STATES PATENTS 1,854,467 4/1932 Fourness137496 2,366,144 12/ 1944 Griswold 137-496 2,407,761 9/ 1946 McPherson251-46 FOREIGN PATENTS 690,897 4/ 1953 Great Britain.

M. CARY NELSON, Primary Examiner.

R. J. MILLER, Assistant Examiner.

1. A CHECK VALVE FOR BLOCKING A FLUID LINE WHEN THE FLUID THEREIN ISSUBJECTED TO BACK PRESSURES OF EXTREMELY SMALL MAGNITUDE: SAID CHECKVALVE COMPRISING A BODY HAVING AN INLET PORT, AN OUTLET PORT, AND ANINTERNAL CAVITY; A FLEXIBLE CONTINUOUS UNOBSTRUCTED DIAPHRAGM EXTENDINGACROSS THE CAVITY WHEREBY THE CAVITY IS DIVIDED INTO FIRST AND SECONDCHAMBERS; AND A BOSS SECURED TO THE BODY AND PROJECTING INWARDLY THROUGHTHE FIRST CHAMBER WHERE IT TERMINATES IN A SUBSTANTIALLY PLANAR SEATINGFACE LOCATED PARALLEL AND IN CLOSE PROXIMITY TO THE DIAPHRAGM; THE BODYBEING PROVIDED WITH A FIRST PASSAGE INTERCONNECTING THE INLET PORT ANDFIRST CHAMBER, A SECOND PASSAGE WHICH COMMUNICATES WITH THE OUTLET PORTAT ONE END AND AT ITS OTHER END TERMINATES AT THE SEATING FACE OF THEBOSS IN THE FORMATION OF AN ORIFICE, AND A THIRD PASSAGE FORESTABLISHING COMMUNICATION BETWEEN THE OUTLET PORT AND THE SECONDCHAMBER; THE DIAPHRAGM BEING ADAPTED TO FLEX AWAY FROM THE SEATING FACESO AS TO REDUCE THE VOLUME OF THE SECOND CHAMBER WHEN THE PRESSURE ATTHE INLET PORT EXCEEDS THE PRESSURE AT THE OUTLET PORT WHEREBY